使用 Dapper 映射多个复杂类型属性

Question

我有以下 Dapper 查询：

var orderModels = db.Query<OrderModel>(@"
SELECT
    o.[Id],
    o.[CustomerId],

    o.[DeliveryAddress_FirstName],
    o.[DeliveryAddress_LastName],
    o.[DeliveryAddress_Line1],
    o.[DeliveryAddress_Line2],
    o.[DeliveryAddress_City],
    o.[DeliveryAddress_State],
    o.[DeliveryAddress_PostCode],
    o.[DeliveryAddress_Country],

    o.[BillingAddress_FirstName],
    o.[BillingAddress_LastName],
    o.[BillingAddress_Line1],
    o.[BillingAddress_Line2],
    o.[BillingAddress_City],
    o.[BillingAddress_State],
    o.[BillingAddress_PostCode],
    o.[BillingAddress_Country]
FROM
    [Order] o
");

我想将其加载到以下结构的数据模型中：

public class OrderModel
{
    public int Id { get; set; }
    public int CustomerId { get; set; }

    public AddressModel DeliveryAddress { get; set; }
    public AddressModel BillingAddress { get; set; }
}

public class AddressModel
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Line1 { get; set; }
    public string Line2 { get; set; }
    public string City { get; set; }
    public string State { get; set; }
    public string PostCode { get; set; }
    public string Country { get; set; }
}

我尝试查了一下，Dapper 中有一个名为 multi-mapping 的功能。但是，当我不连接多个表的结果时，我无法弄清楚如何在我的用例中使用它。

对于像 Dapper 这样的 ORM 来说，这感觉是一个非常常见的场景，所以我确信我只是错过了一些明显的东西。如果您对 Dapper 有更多了解，请提供帮助。

实现这一目标的最佳方法是什么？

Answer 1

Dapper 不关心连接，您只需要为其提供正确的选项字段，splitOn例如：

    var orderModels = db.Query<OrderModel, AddressModel, AddressModel, OrderModel>(@"
    SELECT
        o.[Id],
        o.[CustomerId],

        o.[DeliveryAddress_FirstName] AS [FirstName], // Field names should match properties of your model
        o.[DeliveryAddress_LastName] AS [LastName],
        o.[DeliveryAddress_Line1] AS [Line1],
        o.[DeliveryAddress_Line2] AS [Line2],
        o.[DeliveryAddress_City] AS [City],
        o.[DeliveryAddress_State] AS [State],
        o.[DeliveryAddress_PostCode] AS [PostCode],
        o.[DeliveryAddress_Country] AS [Country],

        o.[BillingAddress_FirstName] AS [FirstName],
        o.[BillingAddress_LastName] AS [LastName],
        o.[BillingAddress_Line1] AS [Line1],
        o.[BillingAddress_Line2] AS [Line2],
        o.[BillingAddress_City] AS [City],
        o.[BillingAddress_State] AS [State],
        o.[BillingAddress_PostCode] AS [PostCode],
        o.[BillingAddress_Country] AS [Country]
    FROM
        [Order] o
    ", 
(order, deliveryAddress,  billingAddress) => {
   order.DeliveryAddress = deliveryAddress; 
   order.BillingAddress = billingAddress; 
   return order; 
},
splitOn: "FirstName,FirstName");

本文对此进行了解释。

此外，选择的字段名称必须与 Dapper 的模型属性名称匹配才能自动找出映射。